To complete my series posts on writing Trust Association Interceptors (TAI’s) for Websphere Application Server I wanted to show a real-life example. Not a good example necessarily but an example never the less… 🙂
The below example is a very simple TAI that simply does the following:
- The initialize() method reads a cookie name from the configuration done in the Websphere Application Server ISC. It illustrates how you can configure a TAI externally without having to hard code it.
- The isTargetInterceptor() method looks at the request and sees if a cookie with the configured name is available. If yes it continues to process the request and if not it aborts processing (from the TAI point of view).
- The negotiateValidateandEstablishTrust() method does the actual work by simply telling WAS that the username of user is the value from the cookie.
As you see writing a TAI is very simple but extremely powerful. Imagine what could be done if you did SSO between Websphere Application Server and Lotus Domino.
import java.util.Properties;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.ibm.websphere.security.WebTrustAssociationException;
import com.ibm.websphere.security.WebTrustAssociationFailedException;
import com.ibm.wsspi.security.tai.TAIResult;
import com.ibm.wsspi.security.tai.TrustAssociationInterceptor;
public class ExampleTAI implements TrustAssociationInterceptor {
// declarations
private String cookie = null;
@Override
public void cleanup() {
}
@Override
public String getType() {
return String.format("Example TAI %s", this.getVersion());
}
@Override
public String getVersion() {
return "1.0";
}
@Override
public int initialize(Properties props)
throws WebTrustAssociationFailedException {
System.out.println("ExampleTAI.initialize()");
// read properties from configuration in WAS
this.cookie = props.getProperty("cookieName");
// return 0 to indicate success
return 0;
}
@Override
public boolean isTargetInterceptor(
HttpServletRequest req)
throws WebTrustAssociationException {
System.out.println("ExampleTAI.isTargetInterceptor()");
for (Cookie c : req.getCookies()) {
if (c.getName().equals(this.cookie)) return true;
}
return false;
}
@Override
public TAIResult negotiateValidateandEstablishTrust(
HttpServletRequest req,
HttpServletResponse res)
throws WebTrustAssociationFailedException {
System.out.println("ExampleTAI.negotiate...()");
for (Cookie c : req.getCookies()) {
if (c.getName().equals(this.cookie)) {
// send 200 to signal we're okay
return TAIResult.create(HttpServletResponse.SC_OK,
c.getValue());
}
}
// not authenticated
return TAIResult.create(HttpServletResponse.SC_UNAUTHORIZED);
}
}
